If your daughter didn't make the team, she doesn't have the skill needed. If she wants to make it next year she'll need to work very hard to develop it.
How many games (both competitive and random pick-up) is she getting a week? If you want to get better at it, there is no substitute at all for time spent doing an activity. Skill in a sport like basketball (reading other players, anticipating bounces, knowing when to jump to block a shot, reading plays, handling the ball when someone is trying to take it from you, knowing when to take shots, knowing which shots and plays are high percentage, etc.) comes directly from time spent in the game.
Now, once you have a base of games played, then comes the need to drill and practice until every action becomes intuitive and second nature. Time you can't spend on the court competitively has to cover the sports specific training for strength and endurance for the activity - lots of suicides, agility drills, hand/eye coordination stuff, weight training, dribbling, passing, shooting, etc. Every action needs to be practiced and perfect. And you need someone watching her play to figure out which drills she will most benefit from.
If she really wants it, she can improve and go for it next year . . . but you should expect to be spending significant time to achieve this goal. You want to be spending around ten hours a week to really be learning enough to become competitive in a sport, and will need access to a reasonable place to play for that period. It's a long, hard road. Expect to be paying for clubs, planning around practices, driving her all over the place so she can play in games, helping her look up tutorials and drills online, timing her pre-school exercises, and then packing lunch for her post-school games. There is no short cut, and no substitute for time.
I've known very few people who were able to be competitive without working hard at their sport . . . but a huge number of people who were only able to be competitive by devoting big chunks of time to developing and maintaining high skill levels. The funny thing is, those who didn't have to work hard at the beginning tend to be the ones who have the most trouble later on - because they don't develop the kind of work ethic necessary to continue. That grit and drive is what competitive sports are all about (it's the single best thing that sports can impart on a young person), and it can be a learned skill.